The present invention relates to pupillary measurements and, more particularly, to a system, method and device for measuring pupillary distance, taking into account relevant physiognomy and the desired frame of the measured individual, and so facilitating online purchases of prescription frames.
Traditionally, measuring pupillary distance required an individual to utilize the services of an optician using a ruler or specialized equipment, usually by visiting an optical store, to obtain such measurements. Such measurements include pupillary distances and segment heights, wherein the pupillary distances are the horizontal distance between each eye-pupil and the center of the frame nose-bridge (always necessary to make eyeglasses), and wherein the segment heights (not required for single vision eyeglasses) are the vertical distances (for progressive eyeglasses) between each eye-pupil, and (for bi-focal eyeglasses) between each top of the eye's lower eye-lid, and their corresponding eye-frame.
In-store measurements were the norm because even small pupillary measurement error can make prescription eyeglasses exhibit prismatic behavior, causing squint, headaches, and dizziness. The importance of centering an optical lens in alignment with the individual's eye pupil is one of the key factors for making prescription eyeglasses successfully.
Recently, methods of measuring pupillary distance have been developed so the individual need not employ the services of an optician—i.e., remote methods. One popular method only suitable for single-vision eyeglasses consists on taking a picture of the individual while placing the back-side of a credit card, a CD/DVD or an object of a commonly known length on his/her chin in order to be able to obtain the scale of the picture and calculate the inter-pupillary distance from the picture. However, this method is not suitable for, among other things, multifocal (progressive) eyeglasses because it does not account for the desired frame the individual wants to wear, leaving the segment heights unknown relative to the position of the desired frame seated on the individual's nose. This method is also not suitable for an individual with an asymmetrical face, as the actual pupillary distances from the nose to their corresponding right and left eyes may differ from the value obtained from a single inter-pupillary measurement. Moreover, this method may also requires the individual to get assistance of another person to take the picture; otherwise risk the pupillary measurement error(s) and its associated effects mentioned above.
Another popular remote method consists on having the individual taking his/her own measurements in front of a mirror using a ruler; either with or without the assistance of another person. Since even experienced opticians have difficulty taking their own measurement in a mirror, this method is prone to pupillary measurement error(s) and its associated effects mentioned above.
Yet, another possible remote method could consist of using a software application which superimposes pictures of a frame over pictures of the individual's face without wearing a frame; the method is currently used to virtually try-on different frame designs in order to see how they look. Even if an attempt is made to get measurements from those pictures, the elevation of an optical frame on a face depends on how high the frame's nose-support seats on the person's nose, which depends on the shape of the frame's nose-support and the physiognomy of the person's nose, the desired frame's pantoscopic angle, and the height of the ears supporting the frame's temple ends.
As can be seen, there is a need for a system, method and device for measuring pupillary distance, taking into account relevant physiognomy and the desired frame of the measured individual, and so facilitating online purchases of prescription frames.